As emission standards become ever more strict, there is an increasing need to minimize the volatile organic content (VOC) of coating compositions. There is a continuing need to provide water-borne coating compositions of increasingly lower VOCs. It is an object of the present invention to provide polyester coating compositions of low or very low VOC content, approaching the zero VOC content of powder coatings, and also to provide coating compositions which are UV-stable.
U.S. Pat. No. 3,974,115, the teachings of which are incorporated herein by reference, describes water-borne polyester coating compositions in which the polyester is formed using polycarboxylic acid monomers of which a major portion comprises aromatic dicarboxylic acids. While compositions are described in this patent which are substantially free of VOCs, the coating compositions lack UV-stability.
U.S. Pat. No. 5,262,494 the teachings of which are incorporated herein by reference, describes polyesters in which the acid monomers consist of hexahydrophthalic acids and polyols including 1,4-cyclohexanedimethanol. These polyesters, however, are not water-soluble. U.S. Pat. Nos. 3,668,275 and 2,901,466 also describe polyesters containing cycloaliphatic dicarboxylic acids.